RoadTest: GW Instek MDO-2072EX MSO / MDO Oscilloscope
Author: fmilburn
Creation date:
Evaluation Type: Test Equipment
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: Several other oscilloscopes in this class have a waveform generator but not the spectrum analyzer, DMM, and power supply. The Keysight DSOX1102G will be used as a comparison where capabilities overlap.
What were the biggest problems encountered?: None of consequence.
Detailed Review:
Introduction
The GW Instek MDO-2072 EX is a mixed domain oscilloscope with a spectrum analyzer, dual channel 25 MHz arbitrary waveform generator, 5000 count digital multimeter, and dual 5V / 1A DC power supply. Bandwidths of 70 / 100/ 200 MHz and 2 or 4 channel versions are available. This makes it well suited for educational facilities and users who's bench space is at a premium. The review starts with an unboxing, overview of features, and some overall impressions followed by the main body of the RoadTest that:
Unboxing
The instrument came well packaged in a single box and without damage.
Including in the box are:
Summary: While all parts were received well packaged and in good condition the power cords were for a European customer rather than North American.
Features and Specifications
For feature and specification comparison the Keysight DSOX1102G is included in the abbreviated table below since it is a well equipped oscilloscope in the same price range and I am familiar with it. There is a comparison of the Keysight to entry level Rigol and Siglent oscilloscopes here. See the datasheet and user manual for additional information on individual instruments.
Feature | GW Instek MDO-2072 EX | Keysight DSOX1102G |
|---|---|---|
| Bandwidth | 70 MHz (100 and 200 MHz available) | 100 MHz hackable to 200 MHz |
| Sample Rate | 1 GSa/s | 2 GSa/s |
| Memory Depth | 10 Mpts per channel | 1 Mpts |
| Segmented Memory | Yes | Yes |
| Waveform Update Rate | 120 k/s max | 50 k/s |
| Analog Channels | 2 + 1 Ext Trigger | 2 + 1 Ext Trigger Ext Trigger can be digital input |
| Triggering | Edge Pulse Width Video Pulse Runt Rise / Fall Slope Timeout Alternate Event-Delay Time-Delay Bus | Edge Pulse Width Video Pattern Rise / Fall Time Setup / Hold |
| Time Base Range | 1 ns/div to 100 s/div (1-2-5 increments) | 5 ns/div to 50 s/div |
| Vertical Sensitivity | 1 mV to 10V div | 5 mV to 100 V/div |
| Data Logging | Up to 1000 hours | No |
| Mask Testing | Yes | Yes |
| Math | FFT Add Subtract Multiply Divide User Expressions with numerous options | FFT Add Subtract Multiply Divide |
| Display Quality | 8" WVGA Low Glare Medium Font | 7" WVGA Low Glare Medium Font |
| Serial Decoding | I2C UART SPI (4 channel only) CAN LIN no additional cost | I2C UART / RS232 SPI CAN LIN option with additional cost |
| Wave Generator | 25 MHz dual channel 14 bit, 200 MSa/s sample rate Sine, Square, Ramp, Pulse, DC, Noise, Lorentz, Exponential, Rise, Exponential Fall, Haversine, Cardiac | 20 MHz single channel Sine, Square, Ramp, Pulse, DC, Noise |
| Digital Multimeter | 5000 count DC Voltage 6 ranges 50mV - 1000V DC Current 3 ranges 50mA - 10A AC Voltage 5 ranges 50mV - 700V AC Current 3 ranges 50mA - 10A Resistance 5 ranges 500Ω - 5MΩ Diode Test max 1.5Vf Temperature -50C to 1000C Continuity Beeper | 3 digit Voltage |
| Digital Power Supply | 2 Channel 1.0V to 5V range 1 A max output 0.1V increment adjustable | No |
| Spectrum Analyzer | Frequency Range DC - 500 MHz Span 1kHz - 500 MHz Res Bandwidth 1 Hz - 500 MHz Reference Level -50 dBm to + 40 dBm Vertical Scale 1 dB/div to 20 dB/div (1-2-5) 100V max input | No |
Frequency Response Analysis (Bode Plot) | Yes, to 25 MHz | Yes, to 10 MHz |
| Connectivity | USB, Ethernet, Go/NoGo BNC | USB |
| Input Impedance | 1 MΩ 16 pF | 1 MΩ 16 pF |
| Probes | 70 MHz 1x / 10x | 200 MHz 1x / 10x |
| Fan Noise | Moderate | High |
| Training Signals and Education | Separate board available extra cost | Built-in |
| Documentation Quality | Good | Good |
| Status | Current Model | Current Model |
| Approximate Cost, USD | $1050 ($1300 for 100 MHz Model) | $1100 fully optioned 100 MHz |
There are a number of features and specifications deserving further discussion.
Costs are indicative only, see retailer for actual cost. Detailed discussion and findings are covered in the sections below.
Summary: The instrument being tested is feature rich and well positioned for the educational market and might also be suited for a home electronics bench with limited space.
Setup and First Impressions
The GW Instek MDO-2072EX appears physically large (380mm x 208mm x 127mm) in the comparison photo with the Keysight DSOX1102G but is shallow in depth and would not take excessive space on a bench especially given the features.
The top is such that other instruments could not be stacked on it. I don't find the size off putting and on the 4 channel model each channel retains it's own vertical controls which I prefer. The control locations were easy to get used to and the selection buttons / tabs at the bottom worked well with the user interface.
The instrument takes about 28 seconds to boot and then displays a message that all power on tests passed. The firmware was updated as recommended by the user manual to version 1.41 by downloading a file and transferring it via a USB memory stick without issue. It was also necessary to download and install the frequency response app and this was also done without issue.
The probes supplied are rated at 70 MHz. The grounding clips are stiffer and a bit more difficult to open than some. Ground springs that fit over the probes are not provided. Probe compensation is straight forward with the adjustment located at the BNC connection.
Summary: Setup was uneventful and it was possible to find the way around the oscilloscope without referring to the manual too much. Menus aren't too deep and for the most part are intuitive.
Layout
The front panel is laid out in a fairly conventional manner with the addition of the bottom menu keys working nicely with the user interface.
Source: GW Instek User Manual
In addition to what one normally expects to find on the front panel there are ports for the digital multimeter placed bottom left. The option key located near the bottom center is used to select the spectrum analyzer, AWG, DMM, and power supply menus. The writing above the hardcopy key, menu key, and option key is small and difficult to read except in very good light.
Source: GW Instek User Manual
The two power supply outputs and the two arbitrary wave generator outputs are located top right on the rear panel.
Summary: In general the physical interface was easy to adapt to and doesn't get in the way of the user.
Basic Sine Wave
In this section a sine wave will be generated with the AWG and displayed with cursors to demonstrate basic operation. Setup consists of running one of the BNC leads from GEN1 on the rear panel to channel 1 and setting the sine wave to 1V p-p and 100 kHz.
More detail on the AWG will be given below but it is easy to set up. Cursors are different than what I am used to but were quickly figured out without referring to the manual. Probe Voltage needs to be set to 1X for proper readings when using BNC to BNC connections between the AWG and scope so beware when changing back to 10X probes. The horizontal time and vertical voltage settings were done manually and this was quick and easy. Auto setting is also quick. Screen shots can be recorded with a single button press.
Summary: Basic setup is quick and easy. The base display gives the necessary information and is laid out neatly in an easy to read fashion.
Triggering on Noisy Signal / Noise Rejection
A noisy signal can sometimes cause an edge trigger to occur outside of where it is expected. In this demonstration a 1 kHz Sine wave is fed to the GW Instek scope from the Keysight. The default trigger settings being used result in an undesired trigger on the noise as shown below.
The setting for noise rejection and HF / LF rejection are in the coupling tab which required a search in the manual to find. Selecting Noise Reject On causes the scope to trigger where desired. Since the noise is high frequency, choosing HF Reject also allows proper triggering.
Summary: Noise rejection works as expected.
Saving and Recalling Information
The MDO-2072EX can store *.bmp or *png 800x480 pixel images. It can also store up to 20 waveform files in internal memory in a *.lsf format. Stored waveforms can be transferred to up to 4 reference waveforms for direct display. Waveforms can also be stored in comma separated value (*.csv) format and opened in spreadsheets. Settings are stored in a proprietary *.set format.
Individual labels are available for input channels, reference waveforms, and file names. The letters are selected by turning the "Variable" knob and then pushing the "Select" key.
There are numerous options, for example below is a sine wave using saved ink saver mode.
Displaying a reference waveform alongside the current real time display can be useful. The stored waveform must be moved into one of the 4 reference waveform locations. Here the 1 MHz waveform from above has been stored and then displayed in grey alongside a 999 kHz waveform.
Saving settings would be useful in a classroom situation where multiple students are using the same equipment. It is also useful where an experiment or test is repeated frequently. Removing reference waveforms is done with the small R button in the vertical control section which I had to hunt for on first use.
Summary: The file saving and retrieval features are adequate and easy to use.
Arbitrary Waveform Generator (AWG)
The 25 MHz Dual Channel Arbitrary Waveform Generator has 14 bits vertical resolution and a sample rate of 200 MSa/s with 16k memory length. Thirteen pre-built waveforms are provided as seen in the screenshot below.
The waveform settings include the ability to set frequency, amplitude, and DC offset.
Modulation options include AM, FM, and FSK.
Frequency can be swept in a linear or log fashion and there are options available for Start, Stop, Sweep Time, Span and Center
The load impedance can be set to 50 Ohms or High Z. Phase can be set for the channel 1 generator. Other options such as duty cycle can be set for pulse waves.
There is a useful summary view of the state of the waveforms. In the screenshot below both channels can be seen with a sine wave defined on the left and a square wave on the right.
The resultant waves can be seen in the screenshot below.
I find the display clean and informative. On the left can be seen in white font the AWG output. Just below it are the values for the horizontal and vertical grid.
It is possible to load arbitrary waveforms as CSV files and it is also possible to edit files on the instrument as shown by the glitch I've added to the sine wave below.
Summary: The Arbitrary Waveform Generator is flexible, goes to 25 MHz and has two channels. It integrates well into the oscilloscope and will be used to demonstrate other features of the instrument as the RoadTest progresses. By using the math function more complicated waveforms could be generated such as adding noise from one channel to the other.
Advanced Triggering
The MDO-2072EX offers a number of triggering options beyond edge including holdoff, delay, pulse width, video, pulse & runt, timeout, and single shot. Edge triggers can be rising, falling, or either and are demonstrated elsewhere in this RoadTest. Holdoff, pulse width, and single shot will be demonstrated here.
Holdoff is the waiting period before the oscilloscope starts triggering again after a previous trigger point. This can be helpful when bursts are occurring and triggering is desired only on the first pulse in the burst.
Source: GW Instek MDO-2000E_2000EA User Manual
In the contrived example below an arbitrary pulse waveform was generated manually on channel 1 and holdoff is set at the default 4 ns. Perhaps not apparent immediately is that triggering is occurring on different rising slopes and that multiple overlapping bursts are being displayed.
The major divisions horizontally are 5us. By changing the holdoff to something greater than 5us (here 10us) assurance can be obtained that the start of the burst is caught. The horizontal scale can then be changed to better view the burst as shown below.
Pulse Width Triggering is used to catch the following 50 kHz clock signal with a rare intermittent glitch being purposely generated by the Keysight. The glitch can be seen as a brief flash with normal settings but isn't visible most of the time or in the screen capture below.
By turning the persistence up to infinite a glitch becomes visible in the waveform on the left.
It can be seen that the glitch has a pulse width less than 2us. By setting the trigger to pulse width to < 1.6us the glitch is isolated as shown below.
Single Shot was also used in the screen shot above to stop the capture after the glitch was triggered.
Summary: All of the triggering functions tested work as expected. The pulse width triggering test performed above could not be done with some scopes I've tested in the past and can be tricky but worked without issue here.
Cursors and Automatic Parametric Measurement
To demonstrate cursors and parametric measurement the AWG was set to generate a 10 kHz 1V p-p Gaussian (just to be different) waveform with 1.5V offset on channel 1.
The horizontal and vertical cursors were then set to the peak and mid-valley by eye, and the automatic measurements for frequency, period, peak to peak voltage, and low voltage added to the bottom display pane. Up to 8 automatic measurements can be displayed at any one time.
It is also possible to add statistics for the automatic measurements.
A measurement summary can also be displayed in tabular form overlaying the waveform.
Summary: The automated measurements one expects are present and the cursors are easily set manually. Up to 8 automated measurements can be selected for display simultaneously and statistics are also available. The measurement summary is displayed in an easy to read tabular form.
Gate and Zoom
The Zoom function is handy for capturing and scrolling through waveforms. A small window at the top gives a global view with a close-up in the window below. The main features are demonstrated in the short video below.
Summary: Zoom works as expected and has a useful play / pause feature.
Math Functions
While FFT is grouped with the Math Functions in the MDO-2072EX, it will be evaluated with the Spectrum Analyzer in this RoadTest.
The scope has basic and advanced tabs for doing math on the channel. The basic tab allows one channel to be added, subtracted, multiplied, or divided by the other. The advanced tab allows about any reasonable operation desired.
The AWG was set up first with a 1kHz 500mV p-p Sine wave on channel 1 and a 100Hz 2V p-p Sine wave on channel 2.
For basic math the source can be either of the two oscilloscope input channels or reference waveforms that have been previously stored. The user then picks the one operator to be applied. The position and units per division can be modified. In this example channel 2 is added to channel 1 and displayed on the red trace with the same vertical units per division as channel 1 and channel 2.
Advanced math offers a significant number of options as shown in the screenshot below.
Let's say we want to integrate the difference between channel 1 and channel 2. Then the following expression can be entered.
After modifying the time scale the oscilloscope shows the following where the red trace is the integrated result.
Summary: The math and advanced math functions are powerful and easy to use.
Peak Detect
Infrequent glitches can go undetected on the oscilloscope when in normal sampling modes. In the waveform below there is an unseen glitch that appears infrequently and would only appear in a screenshot with luck.
The MDO-2072EX has a peak detect mode where minimum and maximum value pairs are displayed. The red arrow inserted in the screenshot below points to one of the detections from the waveform above.
Summary: Peak Detect works as expected.
Segmented Memory
Segmented memory can be used to capture increased information / number of bursts separated by long intervals as only the bursts with associated timing are stored and not the intervening interval.
Source: GW Instek User Manual
A "RF Burst" was set up on the Keysight and monitored on channel 1 of the MDO-2072EX as shown below. The number of segments to be captured and other information can then be entered behind the acquire button.
Here 600 segments were captured over a period of more than 2 seconds. The screen capture shows the 590th segment out of 600 captured.
It is also possible to use the play / pause buttons to scan through segmented memory.
Summary: Segmented memory on the MDO-2072EX is easy to use, works well, and due to the increased memory can capture more segments than the Keysight DSOX1102G. The Rigol and Siglent used in my previous oscilloscope comparison did not have segmented memory.
Masking
Masking works by creating a template of a defined shape which is compared to an input signal for excursions. It is installed as an application and is accessed through the APP key. Both auto masking and user defined masking are available along with a number of options. Only a high level examination of auto masking was done.
Below a mask defined by Auto Mask was created around a purposely noisy sine wave from the Keysight and monitored.
Simple statistics are available in red on the left bottom of the trace indicating that 100 excursions have occurred out of 13,983 waveforms examined. On the Keysight, excursions are marked with a red dot on the trace so that they are more readily apparent to the user.
Summary: Masks behaved as advertised.
Serial Protocol Decoding
While serial protocol decoding is included in the base cost, SPI is not available on the 2 channel scopes. A quick check of I2C was done to get an idea of what it looks like on the screen using an Infineon XMC 2Go microcontroller development board communicating with an Infineon 3DSense Shield2Go . After configuration with the Bus key the following output is obtained.
Summary: The feature would be useful in an educational setting for introducing students to serial decoding but SPI is missing on the 2 channel oscilloscope models.
Power Supply and Digital Multimeter (DMM) DC Voltage Measurement
The DC voltage measurement capabilities of the DMM and and the power supply were tested together and compared to a Tenma 72-1020 bench multimeter known to be accurate by incrementing the power supply from it's minimum to maximum voltage without a load. Several loaded cases were then checked. The RMS ripple and noise of the power supply were checked using the oscilloscope. Other capabilities of the DMM were then tested separately against the Tenma 72-1020.
The power supplies can output from 1V to 5V in 0.1V increments. Output is limited to 1 Amp and is protected by a resettable fuse. The screen below pops up if current is exceeded which occurred in an unplanned test due to operator error.
The unloaded power supply output voltage was checked on the MDO-2072EX DMM by comparing to a Tenma 72-1020 for both channels and recorded in the table below.
A screenshot of the MDO-2072EX DMM in DC voltage measuring mode is shown below.
The power supply was then loaded with a nominal 10 ohm resistor measured to be 10.19 ohms using a LCR meter with Kelvin 4-wire measurement and tested on both channels using the Tenma 72-1020 to check output voltage.
Both power supply channels are well within the datasheet specification of +/- 3%. The DMM DC voltage is also within the datasheet specification of +/-(0.1% + 5 digits).
A limited number of readings of ripple and noise were made with the MDO-2072EX and found to be under the 50 mV RMS datasheet spec.
Summary: Both power supply channels met the specifications from the datasheet in the areas checked. The DMM also met DC voltage specifications in the areas checked. The power supply has limited adjustment resolution and 1V to 5V range with both channels voltage relative to the same ground. The high voltage range of the DMM was not tested.
Additional Digital Multimeter (DMM) Functions
The 5,000 count DMM has the following features.
| Feature | Range | Accuracy | Comment |
|---|---|---|---|
| DC Voltage | 6 ranges (50 mV to 1000V) | +/- (0.1% + 5 digits) | 10 MOhm Input Impedance |
| DC Current | 3 ranges (50 mA to 10A) | +/- (0.5% + 50 mA) | Accuracy in 50 mA and 500 mA range |
| AC Voltage | 5 ranges (50 mV to 700V) | +/- (1.5% + 15 digits) | Accuracy in 50 Hz to 1 kHz range |
| AC Current | 3 ranges (50 mA to 10A) | +/- (3% reading + 50 mA) | Accuracy in 50 Hz to 1 kHz range |
| Resistance | 5 ranges (500 Ohms to 5 MOhms) | +/- (0.3% reading + 3 digits) | Accuracy up to 500 kOhms |
| Diode Test | Max forward voltage 1.5V | Open voltage 2.8V | |
| Temperature | -50 C to 1000 C | 0.1 C resolution | |
| Continuity | 15 Ohms |
DC voltage is tested in the section above using the instrument power supply. DC current was not tested. AC voltage and current were not tested.
Resistance was tested on a range of resistors and compared against a Multicomp Pro Handheld LCR meter using Kelvin 4-wire measurement and known to be reasonably accurate. Probes provided with the instrument were used for measurement on the MDO-2072EX.
The meters agree within the datasheet specification range. It is not surprising that the 10 Ohm measurement is slightly high given that 2-wire measurement was used for the MDO-2072EX. A screenshot of the DMM in resistance measuring mode is shown below.
Diode measuring mode worked as expected.
Temperature measurement was not tested other than at normal room temperature but worked as expected.
In general the instrument is slow measuring resistance and the continuity mode is slow and care must be taken to make good contact.
Capacitance measurement is not provided by the instrument.
Summary: The DMM met the specifications given in the datasheet. The DMM has more features than the voltage measurement available on most oscilloscopes and provides a useful range. The continuity beep is slow to respond compared to other multimeters in my possession. Current measurement was not tested. Capacitance measurement is not provided. It is expected that many labs will want to purchase a handheld DMM for the times a second meter is needed as well as to supplement the features on the MDO-2072EX.
Frequency Response Analysis (FRA)
The FRA application uses the oscilloscope and wave generator to assist in frequency response analysis. The simple RLC band pass circuit illustrated in the schematic below was created on a breadboard. The values shown for the components were measured with a RLC meter at a frequency of 40kHz.
An online filter analysis tool was used to generate the Bode Plot for the filter for comparison to the experimental value.
The FRA application on the MDO-2072EX was then connected to the breadboarded filter per the diagram on the oscilloscope, setup and run.
The analysis tab leads to a screen that provides cursors for measurement.
The measured center frequency of the filter is 28kHz experimentally versus 28.2kHz calculated.
Summary: The Frequency Response Analysis application is easy to setup / run and provides useful output for analysis.
PC Software and SCPI
The MDO-2072EX comes with a CD but I no longer have a computer with a CD drive so I won't be evaluating whatever is on it. OpenWave software is available for download online but was not tested. The instrument has SCPI commands built in and can communicate with a PC over USB or Ethernet. Gough Lui recently published a tutorial on using SCPI with pyvisa here and a quick demonstration will be done here using some of the techniques he covers.
The SCPI documentation for the MDO-2072 is detailed (over 300 pages) and appears to include about everything the instrument is capable of doing. This demonstration is being done on a Windows 10 machine with NI-VISA installed and Python 3.8 over USB.
The first thing I normally do with a new oscilloscope is set up a 1000 Hz 1V p-p sine wave and see what it looks like. Rather than do it with the knobs we will do that with SCPI. Here is a python script that prints out the oscilloscope ID, generates a 1kHz 1V sine wave on AWG channel 1, auto sets oscilloscope channel 1, and then save a screen shot to a USB memory stick.
# Test pyvisa on GW Instek MDO-2072EX
# 1 Print oscilloscope ID to serial monitor
# 2 Generate 1kHz 1V sine wave on AWG channel 1
# 3 Autoset oscilloscope channel 1
# 4 Store screenshot to USB memory stick
import pyvisa
import time
resource_manager = pyvisa.ResourceManager()
mdo2072ex = resource_manager.open_resource("ASRL6::INSTR")
# ID
print(mdo2072ex.query("*IDN?"))
# AWG
mdo2072ex.write("AWG1:FUNCtion SINE")
mdo2072ex.write("AWG1:FREQuency 1000")
mdo2072ex.write("AWG1:AMPlitude 1")
# Autoset
mdo2072ex.write("AUTOSet")
# Screenshot to USB
time.sleep(5)
mdo2072ex.write("HARDcopy:START")
mdo2072ex.close()
This is what it looks like in the PyCharm IDE after running. The serial monitor in the IDE shows the instrument information - i.e. GW,MDO-2072EX, GES190912,V1.41
Shown below is the screenshot from the oscilloscope sent to USB by SCPI.
Summary: The MDO-2072EX can communicate with a PC over ethernet or USB. The SCPI commands are thoroughly documented and worked well in this brief examination.
Logging Data
The Data Log application is not a conventional data logger but instead logs waveform data or image captures along with the date and time. Up to 1000 hours can be captured. The minimum interval for waveform data is 2 seconds and the minimum interval for screen captures is 5 seconds. In the example below a potentiometer connected to the MDO-2072EX power supply is varied by hand and the data logging app set up to capture screens at 10 second intervals for one minute.
| Data Logging |
|---|
0 Seconds |
10 Seconds |
20 Seconds |
30 Seconds |
40 Seconds |
50 Seconds |
Summary: The Data Logger makes screen captures or records oscilloscope waves / traces in data format at minimum intervals in the 2 to 5 second range for up to 1000 hours. In a short test it performed as expected.
Spectrum Analyzer and FFT
EDIT 30 March 2021: The FFT section has been modified to include recommendations from the manufacturer on using FFT on the oscilloscope.
In addition to the FFT math function found on most oscilloscopes in this class, the MDO-2072EX has a software / firmware spectrum analyzer interface which is one of the reasons I was attracted to this RoadTest. The differences in the time domain and frequency domain will be briefly demonstrated as well as a discussion of the FFT and spectrum analysis capabilities of the instrument.
Conventional FFT calculations in an oscilloscope are done over the entire signal bandwidth up to half the sampling rate. The MDO-2000E series can analyze a defined region of the spectrum with greater frequency resolution. The center frequency, span, and start/stop frequency can be entered in a similar manner to a traditional spectrum analyzer. Since the oscilloscope frontend is utilized, it can accept DC components that would damage traditional spectrum analyzers and frequency sweeping is faster. However, the upper frequency range is limited to 500MHz.
The specifications given below are from the GW Instek User Manual.
Source: GW Instek MDO-2000E_2000EA User Manual
Time and Frequency Domains
The video below is a quick demonstration on use of time domain, FFT, and spectrum analysis on a signal generated by the arbitrary wave generator in the instrument.
AM Signal
Several demonstration waveforms for the spectrum analyzer are available by selecting APP->DEMO->SA on the front panel and will be used here for AM, FM, and FSK waveforms.
In the time domain it can be seen that there is something at 1 MHz signal with varying amplitude.
Turning on FFT the following can be seen. With cursors the sidebands can be picked out 50 kHz away.
Note: This screenshot has been modified from the original post to improve the display.
For comparison, here is the FFT from the same signal displayed on the Keysight DSOX1102G.
The MDO-2072EX can capture more points (1M) and when adjusted properly displays with better resolution.
Turning on the GW Instek MDO-2072EX spectrum analyzer allows easier set up for the frequency domain and improved information display compared to other scopes I have used. With just a few adjustments it can be seen that a 1MHz AM carrier is present and being modulated with a 50kHz signal.
FM Signal
Below is an FM signal with a center frequency of 15 MHz as seen with the FFT (adjustment not optimized).
With the spectrum analyzer it is easier to set up a good view with more information.
FSK
An FSK signal as seen by FFT (adjustment not optimized).
And here with the spectrum analyzer.
Audio Frequencies
To explore the resolution possible in the audio range a 1V p-p square wave was set to sweep from10Hz to 10kHz in one second. The 100Hz resolution band width obtained with 40kHz center frequency and 100kHz span is shown in the short 10 second video that follows. The max holding feature is turned on - can you guess what the trace will look like before watching the video?
Summary: While not the equal of high end traditional spectrum analyzers the MDO-2072EX spectrum analyzer is easier to use in the frequency domain than FFT, gives a better picture, and has improved information display. It has an advantage over traditional spectrum analyzers for inexperienced users in that it can safely handle higher DC voltages due to the oscilloscope frontend. The controls are similar to a traditional spectrum analyzer and work well. The user can start with a wide frequency range for an unknown signal, move the area of interest to the center, set the span, and using the cursors quickly analyze the spectrum of interest.
Conclusion
This was my first opportunity to use a GW Instek instrument and I was impressed. The documentation is very good, the hardware worked as expected, and the user interface easily adapted to. I especially enjoyed learning my way around the spectrum analyzer. Thank you to element14 and GW Instek for selecting me to perform this RoadTest.
Some of the promotional material for the instrument seems marketed towards an educational setting and it does seem well suited to undergraduate labs. It takes up little room on the bench and has a :
The scope has an optional GDB-03GDB-03 oscilloscope training kit that must be purchased separately which might be useful in an education setting but was not tested here.
While some of the hardware is not as full featured as stand-alone instruments, a lab course could be modified to work within their constraints. For example a lab on op-amps could be set up with modern rail to rail chips designed to work on battery power to meet the restrictions of the power supply. An inexpensive but rugged handheld DMM could be added to the bench for current measurement, capacitor measurement, and those labs where more than one meter is needed.
The MDO-2072EX is well suited to educational labs and would also be a good fit for home use with limited bench space. Those with more room have opportunity to look at standalone instruments (including those from GW Instek) tailored to their specific needs.
Thanks for reading. This is a full featured instrument so coverage is necessarily reduced in some areas to fit things in this space. As always your questions, comments, and suggestions are appreciated.
EDIT 30 March 2021: The FFT section of the RoadTest has been modified to include recommendations from the manufacturer on use of FFT on the oscilloscope.
Top Comments
Thanks your great review.
Regarding FFT comparison, the MDO-2000E’s FFT points can be set up to 1M pts (the FFT points refer to the number of sampling data points used to calculate the FFT), and the Keysight…
fmilburn, a neat and enjoyable review.
From the point of view of a person outside electronics and with little knowledge of the subject, I have to say that I have understood the entire article well without…
The difference between "FFT mode" and true spectrum analyser is quite striking. Nice comparison.
I've had good and bad experiences with GW test equipment in the past, interesting to see this one…